<?php
class Form_Element_Name extends Zend_Form_Element_Text {

   public function init() {
           $this->setLabel('Name:');
           $this->setAttrib('maxlength', 30);
           $this->addValidator('Alnum', true, array(true));
           $this->addValidator('StringLength', true, array(0, 30));
           $this->addFilter('StringTrim');
   }
}